MP62 housing score scare

[Godless Commie]

I am rebuilding my engine with forged internals these days..

While I was at it, I wanted to give the supercharger a once over - it was getting pretty noisy lately.

By noisy, I mean, you could hear the blower noise at idle, over the engine.
I was suspecting bearings..

So, I ordered a complete kit, and proceeded to take it apart...

Let me tell you.. The rear cup bearings are a bi-ay-ti-si-eych. I had to make a very special sliding hammer setup to remove them.

What concerns me most is the shape the housing is in.
There are pretty uniform scratch marks covering the upper portion of both sides of the housing. Obvious contact, and the result was noise.

Here are the pics. I am not resizing them on purpose, for detail's sake.









Should I be worried?

In all honesty, there was not any reduction in boost..
Then again, I always got 12-14 psi with a 130/65 mm setup..

Should I lightly sand the scratches out, or just leave it alone?

[99mx5]

I would leave them alone, sanding them would only make more clearance around the rotors. When I had my blower repaired by Magnuson, they drilled holes behind the cups at the intake side and threaded them to push them out with bolts.

[jportwood]

I’ve seen a couple of dismantled high time PD blowers and I’d consider that normal wear. Don’t sand/smooth anything. Put new bearings in it and run that puppy.